Prior art positionally adjustable lighting fixtures combine the support and positional adjustment features in a single joint. Adjustable fixtures such as floodlamp receptacles, extension arm lamps or track lights carry the fixture weight at the point of adjustment and require rigid adjustable joints. These fixtures have rotationally operable members which are continuously frictionally engaged. A user must apply a force sufficient to overcome the ordinary frictional engagement forces to adjust the fixture. The fixtures are often complex and relatively heavy. Adjustment is troublesome inasmuch as the fixture weight must be counterbalanced while the adjustable joint is tightened. The fixture weight continuously bears on the adjustable joint and often necessitates readjustment of that joint. Tighter more secure joints are more troublesome to adjust.